\begin{tabular}{l*{11}{c}}
\hline
                 &\multicolumn{1}{c}{Yr}&\multicolumn{1}{c}{Yr}&\multicolumn{1}{c}{Yr}&\multicolumn{1}{c}{Yr}&\multicolumn{1}{c}{Yr}&\multicolumn{1}{c}{Yr}&\multicolumn{1}{c}{Yr}&\multicolumn{1}{c}{Yr}&\multicolumn{1}{c}{Yr}&\multicolumn{1}{c}{Yr}&\multicolumn{1}{c}{Yr}&\multicolumn{1}{c}{Yr}\\         &\multicolumn{1}{c}{4}&\multicolumn{1}{c}{5}&\multicolumn{1}{c}{6}&\multicolumn{1}{c}{7}&\multicolumn{1}{c}{8}&\multicolumn{1}{c}{9}&\multicolumn{1}{c}{10}&\multicolumn{1}{c}{11}&\multicolumn{1}{c}{12}&\multicolumn{1}{c}{13}&\multicolumn{1}{c}{14}\\ \hline  \emph{Second stage}\\
Enrollment  &      -0.248   &       0.160   &       0.267   &       0.174   &       0.675   &       1.039   &       1.725   &       1.505   &       1.490   &       2.345   &       3.028   \\
            &     (0.454)   &     (0.854)   &     (1.110)   &     (1.387)   &     (1.626)   &     (1.833)   &     (2.132)   &     (2.462)   &     (2.778)   &     (3.169)   &     (3.605)   \\
\hline
Controls    &         Yes   &         Yes   &         Yes   &         Yes   &         Yes   &         Yes   &         Yes   &         Yes   &         Yes   &         Yes   &         Yes   \\
F-stat      &         227   &         230   &         234   &         234   &         232   &         236   &         227   &         225   &         225   &         229   &         227   \\
N           &        3667   &        3654   &        3635   &        3609   &        3577   &        3549   &        3509   &        3478   &        3430   &        3373   &        3335   \\
Mean of Y   &        1.99   &        3.91   &        5.74   &        7.49   &        9.29   &       11.04   &       12.93   &       14.97   &       17.04   &       19.12   &       21.19   \\
\hline
\end{tabular}
